Anytime you have sex without a condom you have a chance of getting pregnant. If you don't want to get pregnant you should have him wear a condom.
you risk getting pregnant anytime you have sex. protected or not. (protection DOES fail...all the time. i know quite a few people who used condoms, b/c or both and now havve 1-3 kids...)
if you don't want to get pregnant use b/c and condoms or don't have sex at all.